Sandblast processing has been known as a processing method to be used in surface-patterning glasses, marbles, plastics, ceramics, leathers, woods, etc. In this method, patterns are drawn by forming a sandblast resist on the surface of a material to be processed, and spraying an abrasive or the like onto the exposed portions of the resist to selectively grind the resist. In particular, fine processing can be achieved by using a sandblasting-resistant photosensitive resin as the sandblasting resist, forming a sandblasting mask pattern by means of photolithography and then spraying an abrasive or the like onto the exposed portions. This technique is applied to the formation of circuit substrates in which metal patterns and insulating patterns are present in admixture, in particular, metal wiring patterns and insulating patterns made of ceramics, luminophors, etc. in plasma display panel (hereinafter referred to simply as "PDP").
PDPs are prepared by forming a cellular or linear structure comprising barrier ribs and priming ribs on a substrate such as glass, providing an electrode and a luminophor layer within the cellular structure or between the linear structures, and introducing a discharge gas thereinto to give a display device. As proposed, for example, by JP-A-2-301934 (the term "JP-A" as used herein means an "unexamined published Japanese patent application"), the cellular or linear structure can be formed by applying on a substrate a composition containing an inorganic powder (e.g., a glass frit having a low melting point) and an appropriate vehicle and drying it to thereby form a paste layer, forming a sandblast-resistant photosensitive resin composition layer thereon, forming a mask pattern for the cell drawing by a lithographic means, effecting sandblasting via the mask pattern to peel off and remove the sandblast-resistant photosensitive resin composition layer, and baking.
The abrasives used in this sandblast processing are those comprising inorganic fine particles having a particle size of 2 to 500 .mu.m such as glass beads, SiC, SiO.sub.2, Al.sub.2 O.sub.3 and
However, the use of these abrasives comprising inorganic fine particles in the sandblast processing results in a large amount of powders of ground electrodes, luminophors, barrier ribs and priming ribs, as well as the fine particles of the abrasives, which are mixed together. The mixture is discarded as wastes as such, since it is difficult to classify the particles in the mixture. This brings about a serious problem in terms of environment.
Under these circumstances, the present inventors have conducted extensive studies, and found out that when specific plastic particles are used as an abrasive in sandblast processing, not only an excellent sandblasting performance can be achieved but also the abrasive in the sandblasting waste matters can be easily removed. This makes it possible to reuse the sandblasting waste matters and to avoid the environmental problem associating the disposal of the sandblasting waste matters. The present invention has been completed based on such findings.